Off-road vehicles such as tractors, lawn and garden tractors, earth movers, or the like vehicles operating on gear transmission or hydrostatic transmission have been there in market for quite some time. Typically, off-road vehicles can be broadly classified into two categories. First, heavy duty off-road vehicles having greater horse power (HP) used for large scale operations and second, off-road vehicles having comparatively smaller horse power for small scale operations. Examples of heavy duty off-road vehicles include agricultural tractors and earth movers whereas, home tractors, lawn and garden tractors, front mount mowers are examples of the second category of off-road vehicles. Further, usage of the smaller HP off-road vehicles in hobby farming is also well known where a person; in his/her spare/leisure time, uses such off-road vehicles for farming, gardening, or ploughing operations.
Off-road vehicles operating on transmission systems allow power generated by an engine to be mechanically transferred towards wheel & axle assembly in a controlled manner. Types of transmission system include gear transmission, power transmission, or hydrostatic transmission (HST). Generally, smaller HP off-road vehicles operating on gear transmission include a manually operated gear lever that is selectively operable in at least four forward/reverse positions. Further, a range-selection lever is also provided within such off-road vehicles, as a part of the gear transmission, to allow the operator with options of selecting range of speed levels within a particular gear shift. Typically, the range selection lever can be positioned between three available speeds levels (high, medium, and low). Thus, the operator driving such off-road vehicles has options of 12 forward and/or 12 reverse speed selections so as to operate the off-road vehicle at the desired speed levels. Such selections can be made by selectively setting the gear and range selection levers at appropriate positions. However, there is at least one prominent drawback associated with smaller HP off-road vehicles operating on gear transmission, especially during hobby farming. During hobby farming the operator needs to frequently manoeuvre and control the off-road vehicle in forward/reverse directions at various speed levels. In order to do so, the operator manually needs to continuously actuate/de-actuate accelerator and simultaneously change various gear and range selection levers. After some time, this process becomes quite tiring and discomforting to the operator. Another problem associated with such gear systems is that the operator needs to shift his hand regularly from the steering wheel to control the levers. This results in loss of concentration from the task on hand thereby resulting in lesser productivity and lesser efficiency.
In order to solve the above mentioned problems upto certain extent some manufacturers have eliminated the use of gears and introduced the system of hydrostatic transmission in the off-road vehicles. Further, in order to actuate the hydrostatic transmission, a treadle pedal control mechanism is introduced and provided on the foot plate of the off-road vehicle. The treadle pedal can be operated in both the forward and reverse directions by heel and toe, respectively, to control the forward and reverse directional movement of the off-road vehicle. The treadle pedal is mechanically connected to the hydrostatic transmission system through a mechanical linkage to allow actuation of the transmission system when the treadle pedal is operated in forward/reverse directions. However, the treadle pedal arrangement comes with its own problems like. For example, the operator positions his foot on the treadle pedal in such a manner that the toe and heel are positioned on the two opposite ends thereof and for providing motion to the vehicle in the forward direction the operator applies pressure by toe and for reverse direction by heel. This is also quite discomforting and tiring to the operator during prolonged operations.
Manufacturers have identified this problem and have replaced the sea-saw type treadle pedal with two separate dedicated pedals positioned adjacent to each other on the foot plate. On pressing the left pedal, the hydrostatic transmission can be actuated to provide forward motion to the vehicle and on pressing the right pedal the vehicle can be provided reverse motion. Additionally, usage of mechanical linkage is also been replaced with electronics systems such as sensors, microcontrollers to control the actuation of the hydrostatic transmission systems. Such electronically coupled hydrostatic transmission systems work quite satisfactorily unless they are not subjected to rough weather/ground conditions and breakdowns. In rough weather/ground conditions, electronic systems are prone to be damaged resulting in frequent breakdowns. Additionally, in breakdown conditions, it becomes quite difficult to take the vehicle from the field to the nearby mechanic resulting in service issues. Thus, there is a need to provide a simpler mechanical linkage system that connects the two dedicated forward/reverse pedals with the hydrostatic transmission system that addresses at least some of the above mentioned drawbacks.
Further, from view of safety standards being maintained while manufacturing of such off-road vehicles in competitive markets, a much safer and secure safety neutral switch 166 needs to be provided. Though safety switches have been present in off-road vehicles for quite some time so as prevent any untoward incident, coupling of neutral switches with the two dedicated pedals in safer manner needs some improvement. Thus, there is a need to provide a mechanical arrangement that addresses this need.
Nowadays, cruise control systems have also been introduced in off-road vehicles. Cruise system when actuated, allows the off-road vehicles to move at a constant speed irrespective of the ground conditions, but only in forward direction. Thus, the cruise system obviates the need of continuously pressing the forward pedal. A spring-loaded cruise control lever is provided adjacent to the seat of the operator and mechanically coupled to the hydrostatic transmission actuation means to provide its actuation in forward direction only. However, in order to disengage the cruise control lever from the hydrostatic transmission or, to position the cruise control lever in its neutral position, the cruise control lever is mechanically coupled with the two brakes (LH & RH). It is known that when both the LH & RH brakes are applied, the mechanical linkage allows the cruise control lever to be positioned in its neutral position. However, due to the fact that such mechanical linkages have more number of parts, they are quite complex in their structure and difficult to be maintained. Additionally, cost and maintenance problems are also present in such mechanical linkages. Thus, there is a need to provide a much lesser mechanical linkage that has less number of parts and solves at least some of the above mentioned problems.